Add link to Day.js format reference

[DarkFox]

Proposed Change

Add a link to the Day.js Format docs page to the eventDateFormat field in the documentation.

Related issues

Fixes #1505

Type of change

Please delete options that are not relevant.

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [X] Documentation update
• [ ] Other (build / ci etc.)

Checklist

• [X] My code follows the style guidelines of this project
• [X] I have performed a self-review of my code
• [X] I have commented my code, particularly in hard-to-understand areas
• [X] I have made corresponding changes to the documentation
• [X] My changes generate no new warnings
• [X] Any dependent changes have been merged and published in downstream modules

[sourcery-ai[bot]]

🧙 Sourcery has finished reviewing your pull request!

---

Tips

- Trigger a new Sourcery review by commenting `@sourcery-ai review` on the pull request. - You can change your review settings at any time by accessing your [dashboard](https://app.sourcery.ai): - Enable or disable the Sourcery-generated pull request summary or reviewer's guide; - Change the review language; - You can always [contact us](mailto:support@sourcery.ai) if you have any questions or feedback.

[marksie1988]

Thanks, that has now been merged